I repeated your dummy bookings and got the same results. But, then I started going on for more days, and I figured out if you choose 4 or more days, AWDs no longer give you any discount. It's also different prices if you choose different residency. Weird

Edit: I did some more "analysis" and found out this is due to the fact that basic rate (per day) without AWD changes a lot depending on time of rent (1-2d=53$, 3d=47$, 4d=27.1$, 5-6d=17.2$, 7+d=15.2$), while with AWD this rate is much more constant (1-2d=35.5$, 3-6d=34.41$, 7+d=32,59$). So AWDs only make sense for short period of rent, while basic rate / day is lower than one without AWD.